The Four Horsemen would ride in a car to and from the Court together to coordinate positions and arguments. They were bitterly opposed to the New Deal policies for unemployment and economic recovery, and they invalidated state laws regulating labor and business relations.[4] The Four's votes kept Congress and the states from regulating the economy.[4] These actions led many observers to the conclusion that the Court was likely to be obstructive to all legislative efforts to cope with the depression, and to remain wedded to the precedents of the Lochner era.[1] Some academics argued that the Court's aversion to 'regulated capitalism' confronted the country with "the question not how governmental functions shall be shared, but whether in substance we shall govern at all."[3]

The result of these dynamics was a steady drift of the Court towards a crisis; the 1935 term was labeled by Justice Stone "one of the most disastrous in [the Court's] history."[3]:282–284 New Dealers decried the Court's actions as "economic dictatorship", and some communities even hanged the justices in effigy.[3]

It was the success of the Horsemen in striking down New Deal legislation that led to Roosevelt's court-packing scheme, a controversial proposal in February 1937 to appoint more Justices in order to change the composition of the Court.[4] This was rendered unnecessary when Justice Roberts, who had supported the Four Horsemen on several decisions during the 1935-36 term, sided with the Three Musketeers in a landmark minimum wage case in March 1937 (known as "The switch in time that saved nine"). This, together with the retirement of Van Devanter in June 1937 and his replacement by Hugo Black ended the Four Horsemen's domination of the Court.[4] Black and Roosevelt considered the Four the "direct descendants of Darwin and Spencer."[4]